26th October


Solar activity was high. At 25/1503 UTC, Region 1882 (S08E54,
Dao/beta-gamma-delta) produced an X2 flare that was associated with
Types II (2078 km/s) and IV radio emissions with another Castelli U
radio signature including a 370 sfu Tenflare. SOHO/LASCO C2 coronagraph
imagery depicted a partial-halo CME emerging from the east limb
beginning at 25/1512 UTC. WSA-Enlil model output suggest this CME will
merge with the ejecta from the 24 October M9 flare and arrive on the
28th.

Region 1882 also produced six M-class events, including an M1 flare at
26/0937 UTC. A Type II (1275 km/s) radio sweep was reported with this
flare, beginning at 26/0931 UTC and dimming was apparent in SDO/AIA 193
imagery south of the region. This event has yet to be observed in
available coronagraph imagery. Region 1882 continued to evolve in both
area, spot count and magnetic complexity.

Regions 1875 (N07W44, Ekc/beta-gamma-delta) and 1877 (S13W23,
Dhi/beta-gamma) remained the largest on the visible disk. Region 1875
grew slightly while 1877 was relatively stable. Between 26/0442-0747
UTC, EUV dimming was observed in SDO/AIA 193 imagery south of and
between Regions 1875 and 1877. A CME was subsequently observed in
SOHO/LASCO C2 imagery emerging from the west beginning at 26/0700 UTC.
This event has not yet been modeled, but a preliminary analysis using
available coronagraph imagery suggests it was moving at approximately
400 km/s and may have an Earth-directed component.

A second dimming event was observed between 26/0827-1015 UTC in the same
vicinity and brightening was evident in Regions 1875 and 1877 around the
same time as the M1 flare from Region 1882. This event has not yet been
observed in coronagraph imagery. Finally, a filament eruption was in
progress in the southwestern quadrant at the time of this writing.

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